We propose to use the 3-wave (1984, 1986, 1988) Longitudinal Study of Aging (LSOA) to examine the rates of transition in physical functioning for community dwelling older adults and the disease-based, social support based and behaviorally based determinants of decline and improvement. While earlier studies have focused on functional decline, little is known about the characteristics of those who improve versus those who are stable. Since the degree of functional transition has important policy implications, we propose to estimate transition rates using alternate definitions of functional impairment in order to determine the sensitivity of transition rates and projections to variations in definition. Finally, we will examine the inter-relationship between functional change and changes in living arrangements, particularly moving into and out of the homes of caregivers. The Specific Aims of the investigation are: (1) To determine the two-year and four-year transitional probabilities of stability and change in functional health status. Transition rates will be calculated for the sample as a whole as well as for the subgroups of major population strata; (2) To extend analyses of predictors of decline among well-functioning older persons to groups with moderate and marked functional limitation. These analyses will examine the predictors of stability and change (including improvement) in functional health ascertaining whether the predictors are comparable for persons with varying degrees of baseline functional limitation; (3) To investigate whether the results for Specific Aims (1) and (2) differ when alternate classifications of functional health status are applied. Results will provide a way to examine the sensitivity of functional health transitions to variations in definition and operationalization; (4) To examine consequences of changes in functional health status for changes in living arrangements between 1984, 1986, and 1988. Results from Specific Aim (3) will be used to determine which indices of functional health should be employed, to minimize risk of bias due to the definition of functional health being applied.